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Bryan72D

Troubleshooting YZ400F electrical system

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I appear to be having electrical issues with my bike. Everything mechanical is either like new or new. Does anyone know of a good resource that'll tell you how to trouble shoot the system? I've done it things like air conditioners and cars, so I'm familiar with the concept, just don't know things like ohm loads, etc. for the various components. I'd like to save the roughly $80 it takes to have the shop diagnose my problem.

Thanks,

Bryan

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Thanks for the advice. I have a Clymer manual for it, but it doesn't have ohm loads, etc. It does have a good wiring diagram that is in color, so I can start chasing grounds, etc. I also just found a factory manual with trouble shooting procedures, so I can start on that as well.

It's hard to start, but will fire with a small amount of ether. It is sparking, but it looks pretty weak. It also takes a lot of care to get it beyond idle w/o flaming out. Once it's in the upper RPMs, it runs strong, but has some popping on deceleration. The valves are in spec, the header is torqued properly with the correct gasket, and it's sealed to the pipe. The jetting is per FMF spec on the pipe.

Thanks,

Bryan

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Throttle Position sensor? Mine was bad when I bought it and gave me trouble for 2 days trying to figure it out. Unplug the TPS and try to start it, if it lights right away you either need to adjust the TPS or it may be beyond adjusting... Ill give you the specs if you need them

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I ended up taking it to the dealer for a diagnostic. I managed to do a solid test on everything but the stator. Since everything else was good, my guess is I'm out a stator.

Thanks,

Bryan

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